Abstract: In this paper，the application and development of ultrasound enhancement in membrane separation processes are reviewed. Applications of ultrasound to enhancing membrane separation including filtration，assisted membrane cleaning and mass transfer membrane process are presented，and the factors influencing the ultrasound enhancement are discussed. Furthermore，the effects of ultrasound irradiation on membrane structure are summarized. It is clear that，in spite of improved performance of membrane separation，ultrasound waves have be used with care.